The present invention relates to an imaging device, and, more particularly to a digital camera and associated method of enabling a selectively and/or manually adapted white balance control for improving image reproduction.
Electronic imaging devices such as digital cameras are becoming increasingly commonplace for capturing still images. Such devices typically employ a photodetector for converting light incident to a lens thereof into an electronic signal representative of an image. Yet, processing incident light in this manner often results in the photodetector erroneously converting the natural image color. As color of the incident light is translated by the photodetector in accordance with a color temperature of a light source rather than natural color as observed by the human eye, variability in natural color reproduction often results; this variability is known in the art as “white balance.” Accordingly, imaging devices employ a white balance control in order to compensate for this condition.
For example, in color processing, a ratio of Red:Green:Blue (R:G:B) color values, typically, the ratio is adjusted to 1:1:1 by controlling the white balance of (R) and (B) color components via a signal processing system of the imaging device. Thus, automatic white balance control is based on the assumption that all colors in a screen display are integrated into achromatic color. However, an image which departs from this condition, such as an image which exhibits a disproportionate monochromatic color of red for example, or an image subject to a particular lighting condition, would still suffer from improper color reproduction. Although control is achieved through a simultaneous control of (R) and (B) color components as above mentioned, and flexibility in controlling white balance may be further improved by independent adjustment of (R) and (B) color component gain, even such independent adjustment often does not yield desirable natural color reproduction.
Thus, to prevent the introduction of improper white balance, further imaging processes are employed. For example, an area division is performed for partitioning a display of the imaging device to process the partitions individually, likewise, a determination may be made in accordance with an algorithm as to whether data is to be utilized as control data for the automatic white balance based on a degree of color saturation. Yet, even with these additional processes, it is still difficult to control the automatic adaptation of white balance, resulting in improper natural color reproduction in the captured image.
As such, most imaging devices such as digital video cameras and digital still cameras employ a manual white balance control function and/or a preset white balance control function. The manual white balance control function enables an operator to independently adjust white balance. Conversely, the preset white balance control function may set a white balance gain to predetermined value depending upon the application, for example, imaging outdoors or under fluorescent lighting. In this way, such manual and/or selectable white balance controls help the imaging device to reproduce images that are not particularly well suited to automatic white balance control. However, in manual and selectable white balance control schemes, operators have difficulty creating consistent results due to the inability to identify settings and/or manipulate the white balance in a systematic manner.
As such, a white balance control and related methodology are desired for integration with an imaging device, the control being devoid of the aforementioned limitations, capable of providing an improved natural color reproduction, and employing a simplified manual setting operation.